裂解气中NO,AsH_3,COS等杂质的色/质联用测定研究

 以气相色谱 /质谱 (GC/MS)的选择离子监测 (SIM )测定方式对裂解气中的一氧化氮、砷化氢、羰基硫、硫醚、硫醇等杂质进行了测定。针对一氧化碳、二氧化碳、乙烷、乙烯及氮气对一氧化氮测定的干扰 ,分别采取色谱分离和扣除响应的方法对其予以排除。考察了裂解工艺气物流对所选择离子的测定的干扰情况。对实际工艺气中的上述杂质进行了测定 ,结果一氧化氮的检出限为 10 0nL/L。     

高纯甲烷纯气体中的杂质分析——CCQM K66国际比对

针对国际CCQM组织的K66高纯甲烷纯度分析关键比对,建立高纯甲烷中杂质的分析和定量方法.根据标准物质的制备过程和对稀释气中杂质的分析结果,对比对过程中的测量不确定度进行了评定.比对样品甲烷中氩气、氮气、乙烷和二氧化碳含量的测定结果分别为2.005、3.601、1.477、2.615 μmol/mol,相对扩展不确定度(k=2)分别为1.5%、4.5%、1.5%、1.6%.     

口腔气体检测仪校准装置的研制

利用研制的三通道渗透管装置发生摩尔分数范围为0.1~1.0μmol/mol的硫化氢、甲基硫醇、二甲基硫醚混合气体,用于校准检测口腔气体检测仪。校准装置可以在固定输出总流量不变的情况下,快速改变发生硫化物的摩尔分数。对校准装置的温控系统和流量系统进行了测试,通过总硫分析仪对校准装置发生的低含量硫化物的量值进行了比较和验证。该校准装置发生的低含量硫化物量的相对扩展不确定度不大于6.8%(k=2)。     

氦气分析用杂质成分气体标准物质研制

采用称量法研制了氦气中微量氖、氢、氧、氮、甲烷、二氧化碳和一氧化碳7种杂质成分气体标准物质,介绍了称量法制备技术、稀释气中相关杂质的定量等过程,并分别用F检验和回归曲线法对研制的气体标准物质进行了均匀性和稳定性检验。结果表明,研制的氦气分析用杂质成分气体标准物质具有良好的均匀性和稳定性,气体标准物质定值结果为10μmol/mol,定值结果的相对扩展不确定度为1%(k=2)。     

甲烷中甲硫醇气体标准物质的研制

以甲硫醇钠为原料，通过与稀硫酸反应制备甲硫醇。对甲硫醇和甲烷分别进行纯化，采用气相色谱-火焰光度检测器与气相色谱法氦离子放电检测器对纯化后的甲硫醇和甲烷进行纯度分析，甲硫醇纯度（摩尔分数）为99.75%，甲烷纯度（摩尔分数）为99.997%。通过称量法制备了甲烷中甲硫醇气体标准物质。采用气相色谱法火焰光度检测器对标准物质进行了均匀性检验、稳定性考察。研制的甲烷中甲硫醇标准物质标称浓度为100μmol/mol,F检验和回归曲线法实验结果表明，在压力0.5～10 MPa范围内，该标准物质具有良好的均匀性和稳定性，定值结果的相对扩展不确定度为2%(k=2)，有效期为12个月。     

水介质对有机硫化物形成影响的模拟实验

利用高压釜反应装置在高温高压下开展了汽油-硫酸镁化学还原反应含水和无水体系的模拟实验,通过气相色谱仪、微库仑仪、毛细管气相色谱/脉冲火焰光度检测器、红外光谱仪及X射线衍射仪对气、油、固三相产物分别进行了分析并对动力学进行了解析,表明主要生成氧化镁、硫、焦炭、硫化氢、二氧化碳以及硫醇、硫醚和噻吩类等有机硫化物;随反应温度升高,反应体系中无机硫转化为有机硫的趋势增强,并主要生成热稳定性高的噻吩硫。 动力学解析表明,含水和无水条件硫酸镁转化反应的活化能分别为68.9和78.5 kJ/mol,证明水存在有利于无机硫向有机硫转化。     

气相色谱法分析超高纯六氟化钨中杂质气体

采用气相色谱-放电离子化检测器分析超高纯六氟化钨中微量杂质气体的含量。自行设计了一套反吹双通路分析系统,当六氟化钨中的气相杂质进入检测器后,将六氟化钨及时反吹出去,避免六氟化钨对仪器的腐蚀。通过正交试验确定了气相色谱仪的最佳工作参数,确定了采用不同的色谱柱进行分析时,仪器的最佳反吹时间。据此提出了气相色谱法分析六氟化钨中的四氟化碳、二氧化碳、六氟化硫、氧气、氮气和一氧化碳等痕量杂质气体。     

微库仑法测定纯镍、纯钴及镍铝合金中的痕量硫

本文提出了用微库仑法测定纯镍、钴及镍铝合金中痕量硫,采用盐酸和过氧化氢溶解金属镍及镍铝合金,同时将硫离子氧化为硫酸根。在氢碘酸一次磷酸介质中,硫酸根被还原为硫化氢。逸出的硫化氢由氮气载入电解池中,库仑滴定所需电量由电子积分器显示,试样中含硫量由校正曲线给出。对于测定0.0004％硫的标准偏差是4×10~(-5)％。     

超声辐射下2-硫代羰基-2H-噻喃和2-氨基-6-硫代羰基二氢吡啶衍生物的高效合成

探索了一种超声辐射下氢氧化钠催化的芳亚乙基丙二腈与二硫化碳或异硫氰酸酯的反应,方便、快速地合成了2-硫代羰基-2H-噻喃和2-氨基-6-硫代羰基二氢吡啶衍生物.本方法具有操作简单、反应时间短、产率高、环境友好等优点.产物的结构经过核磁共振氢谱和碳谱、红外及质谱进行确定.本报道的方法为合成2-硫代羰基-2H-噻喃和2-氨基-6-硫代羰基二氢吡啶衍生物提供了一条有效途径.     

氮气中1 μmol·mol~(-1)硫化氢气体标准物质的研制

介绍了瓶装氮气中1μmol·mol-1硫化氢气体标准物质的研制过程,对称量法制备过程、均匀性、稳定性引入的不确定度进行了评定。该气体标准物质的相对扩展不确定度为Uc=2.0%,k=2,使用有效期为一年,取得了国家一级标准物质证书。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.     

Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water

A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.     

Construction of polyheterocyclic spirotetrahydrothiophene derivatives via sulfa-Michael/aldol cascade reaction

A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).     

Suzuki-Miyaura reactions of the soluble guanylate cyclase inhibitor NS2028: a non-product specific route to C-8 substituted analogues

Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO₄ oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.